Table 4.

Substrate scope of the tandem Friedel–Crafts conjugate addition/asymmetric protonation.^a

entry
1)	76% yield, 93% ee
2)	R = Me (7d) 63% yield, 85% ee
3)	R = allyl (7e) 68% yield, 85% ee
4)	4-Me (7f): 88% yield, 96% ee
5)	5-Me (7g): 83% yield, 95% ee
6)	6-Me (7h): 80% yield, 89% ee
7)	7-Me (7i): 94% yield, 94% ee
	7j
8)	85% yield, 91% ee
	7k
9)b	60% yield, 93% ee
	7l
10)b	63% yield, 92% ee
11)	4-Me (7m): 86% yield, 94% ee
12)	2-Me (7n): 26% yield, 87% ee
	7o
13)	75% yield, 93% ee
14)	4-F (7p): 78% yield, 93% ee
15)	3-F (7q): 76% yield, 92% ee
16)	2-F (7r): 35% yield, 92% ee
	7s
17)	88% yield, 92% ee
18)	R = Me (7t): 61% yield, 85% ee
19)	R = n-Bu (7u): 72% yield, 91% ee
20)	R = i-Pr (7v): 66% yield, 92% ee
21)	R = t-Bu (7w): 29% yield, 84% ee
	7x
22)	80% yield, 90% ee

^aReactions conducted under inert atmosphere on 0.1 or 0.2 mmol scale for 2 h. Isolated yields are reported. Enantiomeric excess was determined by chiral stationary phase SFC.

^b1.6 equiv SnCl₄ were employed.